The tongue is the gateway to the body and is critical in eating, speaking, and breathing. Its function is compromised by disease and also by treatment, such as surgery or radiation for tongue cancer. A key to understanding the relationship between the structure and function of the tongue is to analyze motion changes in localized tongue regions and map them to anatomy. The use of three types of magnetic resonance (MR) images (i.e., high-resolution, cine, and tag) offers new and enhanced capabilities for exploring normal and diseased tongue behavior, advancing our knowledge on a wide variety of speech-related disorders. Quantitative measures derived from MR images, such as tissue compression, expansion, principle strain, and muscle mechanics play a crucial role to characterize normal and abnormal motion of the tongue. However, the critical hurdle currently faced in this field is a lack of tools for accurate, reproducible, and fully automated quantitative characterization of 4D (3D space with time) tongue motion in a normalized space in order to compare and contrast subjects despite their variable tongue sizes, shapes, and motion patterns. A powerful way to measure changes and compromises in tongue structure and function is via a 4D statistical atlas and associated image analysis techniques. Atlases integrate diverse imaging information for individuals and groups, by correlating images with quantitative measurements, and constructing diagnostic tools. The proposed study examines structural and functional changes in the tongues of post- glossectomy patients. In future, this atlas can be applied to any normal or disordered population. The K99 Mentored Phase allows me to transition to a career that studies tongue anatomy, speech science, and vocal tract-related disorders. In addition, I will execute Aim 1: to develop an MRI registration framework and an interactive visualization tool for tongue image analysis using multiple MRI methods. In the R00 Independent Phase, I will pursue Aim 2: to establish a 4D statistical atlas of the tongue that represents the relationship between tongue motion, mechanics, and speech, and Aim 3: to assess the effects of tongue cancer surgery on tongue tip, blade, and body interaction. A mentoring committee has been assembled to guide the research in the K99 phase and facilitate my training. Dr. Stone, who is an expert in speech science and imaging, will provide primary mentorship and guidance in the overall study design. Co- mentor, Dr. Prince, is a world expert in MR image analysis. He will guide me in image analysis. The opportunities provided by this award will not only allow me to pursue potentially ground-breaking research, but will also provide me with valuable mentorship and training for my career as an independent investigator.